backlight: Move the fd out of the select range

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

src/backlight.c

@@ -271,7 +271,7 @@ enum backlight_type backlight_exists(const char *iface)
 
 static int __backlight_init(struct backlight *b, char *iface, int fd)
 {
-	b->fd = fd_set_cloexec(fd_set_nonblock(fd));
+	b->fd = fd_move_cloexec(fd_set_nonblock(fd));
 	b->iface = iface;
 	return 1;
 }

src/fd.c

@@ -31,8 +31,32 @@
 #include <fcntl.h>
 #include <unistd.h>
 
+#include <misc.h> /* MAXCLIENTS */
+
 #include "fd.h"
 
+int fd_move_cloexec(int fd)
+{
+	int newfd;
+
+	newfd = fcntl(fd,
+#ifdef F_DUPFD_CLOEXEC
+		      F_DUPFD_CLOEXEC,
+#else
+		      F_DUPFD,
+#endif
+		      MAXCLIENTS);
+	if (newfd < 0)
+		return fd;
+
+#ifndef F_DUPFD_CLOEXEC
+	newfd = fd_set_cloexec(newfd);
+#endif
+
+	close(fd);
+	return newfd;
+}
+
 int fd_set_cloexec(int fd)
 {
 	int flags;

src/fd.h

@@ -27,6 +27,7 @@
 #ifndef FD_H
 #define FD_H
 
+int fd_move_cloexec(int fd);
 int fd_set_cloexec(int fd);
 int fd_set_nonblock(int fd);